Benzimidazolone-stibonic acids



Patented Apr. 11, 1933 UNITED KARL s'mnrrwom, or rnANxroa'r-oN-mnE-nnn,arr-RED rennin,- or ran sonmr on TAUNUS, AND WALTER'HERRMANN, or FaANxronnoN-THE-MAm, GERMANzAs- SIGNORS TO WINTHROP CHEMICAL COMPANY, 1110., 01 NEW YORK, N. Y., A GORPORA- TION OF NEW YORK IBIEINZIMIDAZOLONE-STIBONIG ACIDS No Drawing. Application and October 28, maa smal'no. 402,540; and swa November 7', 1928 The present invention relates to benzi mida zolone-stibonic acids, more particularly to compounds of the following formula:

. a n v I wherein X stands for hydrogen, a 'l,'halo gen, amino or nitro groups, and stands forhydro'gen or alkyl. 1

We have found that the benzimidazolone stibonic acids have unexpectedlyimportant effects on protozoadiseases, which the known stibonic acids have not to this extent. For the use in therapy the .stibonicacids are preferably transformed into a soluble salt. The benzimidazolone-stibonic acidscan be prepared by causing ortho-diamino-benzene stibonic acids to react with phosgene or by causing diazotized 'amino-benzimidazolones to react with antimonious acid.

The said stibonic acids can'furthermorebe obtained by causing the uantity otchlorocarbonic acid ester whic is required for the reaction with one NH -group to act upon an ortho-diamino-benzene-stibonic acid and by heating the resulting urethane. 4

The formulae in th' 7 following examples and claims only correctly express the position of the stibonic acid residue in the phenyl nucleus, whereas the manner in which the antimony is bound is not de'finitely known.

The chemical formulae of the stibonicacid i are generally written for "simplicitys sake in a manner analogous to that of the arsenic acid. The stibonic acids are, however, really i i always polymeric and contain, according to the manner in which they have been dried, more or less water, about the binding of which within the molecule "nothing certain is known. i

The following examples serve to illus- QPATI'VENT OFFICE mm; our invention, but they are not intend 7 ed to limit it thereto.

(1) Into'a solution of 27 grams of 3- amino- 4-methylamino-benzene-1-stibonic Iacid in with 14 grams of sodiumacetate, phosgene is introduced until it shows an acid reaction to Congo paper. Thereby the 1-methy1- 2- bBllZlHlldaZOlOIle-f)-Stlb011l0} acidof. the fol,- lowingprobable formula:

separates'in-the form of a finely dividedprecipitate-,which' is filtered by suction, w,ashed with water and dried. It forms acolorless powder which is readily solublein diluted alkalies, ammonia or organic bases; when heated, it chars without melting,

(2)-To a solution of 25 grams of 3.4-di-, aminoben'zene-l-stibonic acid in 200 com. of normal caustic soda solution are addedf'l l grams of sodium acetate and-phosgene is introduced until there is an acid reaction to Congo paper. The 2 ben zimidazolone 5 stibonic acid separates and is isolated as de' scribed in Example 1. It forms ajwhite pow organic-bases and has able formula:

' H|0aSb (3) A solution of 28 grams of 3.4-diamino- 5 chlorobenzene-Lstibonic acid in 200 cc.'of

normal caustic soda solution is transformed withphosgeLne in the presence of {sodium acetate as described in Example The V 200 cc. of normal causticsoda solution, mixed I lowing manner: 16 grams of antimony tri-' oxide are dissolved while heating in 200 cc. A r. of water, 50 cc. of glycerine and 35 cc. of" r caustic soda solution of 40 B. For the y transformation process the solution is preferably cooled to room temperature.

When the evolution of nitrogen has "ceased and the solution no longer couples with 1' V resorcine,the solution is neutralized first with forms a Whlte powder whlch readlly hydrochloric acid and then with carbonic acid untilit shows only a feebly alkaline. re- The solution is then filaction to turmeric. tered, cleared with animalcharcoal and"l1y drochloric acid is added until there is an acid reaction to Congo paper, and the 1-methyl-2: benzimidazolone-5-stibonic acid described in Example 1 separates. After filtering by suction, washing and drying, it forms a color less powder which is easily soluble in diluted alkalies, ammonia and organic bases; when heated, it chars without melting.

The diazo solution can also be caused to react with an acid antimony trichloride solution and the resulting double compound can be decomposed by means of caustic soda solution. (5) 18.76 grams of 1-ethyl-5-amino 2- benzimidazolone hydrochloride are diazotized in a'hydrochloric acid solution'and treated with an antimonite solution from 16 grams ofantimony trioxide as described in Example 4, and then worked up. The l-ethyl-Q-benzi-v midazolone-5-stibonic acid thus obtained has the same properties as the benzimidazolonestibonic acid described in Example 4. It has the following probable formula:

(6) 19 grams of annim-abenzimidaza lone-hydrochloride (prepared for instance according to Hager Berichte der deutschen tity of sodium nitrite. The diazo solution is caused to react withan antimonite solution as described in Example 4 and the resultant 2- benzimida zolone-5-stibonic acidis isolated in the usual manner. It forms a white powder whichjis soluble in diluted alkalies, ammonia or the like and has the formula indicated in Example 2.

(7) 22 grams of 5-amino-7-chloro-2-benzimidazolone-hydrochloride, prepared for instance by causing 6-chloro-41-nitro-1.2-diaminobenzene to react with phosgene and subsequently catalytically reducing the nitro compound, are diazotized as described in the Examples 4 to G and caused to react with antimonite solution. j v u The resultant 7 -chloro-2-benzimidazolone- 5=stibonic acid of the probable formula:

soluble in diluted alkalies; when heated, it chars without melting.

- (8) A solution of 3.4-diaminobenzenestibonic acid, obtainable for instance by heating for 45 minutes on the steam bath a solution of 36 grams of 3.4c-diacetyl-diaminobenzene-stibonic acid in 500 cc. of water and 40 cc. of caustic soda solution of 40 B. in order to saponify' the a'cetylgroup, is cooled to 0 C. and hydrochloric acid is added until there is a feebly alkaline reaction to turmeric. Into this soluti'on'12 gramsof chlorocarbonic acid ethyl ester and 12 cc. of 5N caustic soda solution are 7 simultaneously introduced drop 7 by drop while vigorously stirring. and 0001- 0 mg with ice,'so that the'solution shows a V feebly alkaline reaction to "turmeric'untilthe caustic soda solution is consumed. Then the whole isfurther stirredfor 2 hours at room 7 temperature, acidified until there is a pronounced acid re action'to Congo paper and boiled.- The benzimidazolone-stibonic acid described in Example 2 separates in theform of a white precipitate, which is filtered by suction, washed and driedin the'usual manner.'-

- v In the preceding, examples. thestibonic acid residue canyofcourse, also standin 4- or in V 7-positionin thebenzen'enucleus. Furthermore the benzene nucleus can be wholly or partly substituted by substituents such as alkyl, halogen, the amin'o-' or the nitro group.

' Quite-generally speaking there can stand in I-position instead of the methyl group (Example 1) or-the ethyl group (Example 5) also anyhigheralkyl.

Weflc1a,1m: p 1. Aco pound'of the following probable formulaz 1 V I wherein one X stands for chlorine, the other Xs stand for hydrogen and Y stands for hydrogen or alkyl.

2. A compound of the following probable formula:

tures.

KARL STREITWOLF. ALFRED FEHRLE. WALTER HERRMANN. 

